Aromatic L-amino acid decarboxylase inhibitor

Aromatic L-amino acid decarboxylase (AADC) inhibitor is a class of medication that inhibits the enzyme aromatic L-amino acid decarboxylase, also known as DOPA decarboxylase. This enzyme is crucial in the biosynthesis of neurotransmitters such as dopamine, serotonin, norepinephrine, and epinephrine. By inhibiting this enzyme, AADC inhibitors can alter the levels of these neurotransmitters in the brain and other parts of the body, making them useful in the treatment of various neurological and psychiatric disorders.

Mechanism of Action

Aromatic L-amino acid decarboxylase inhibitors work by blocking the enzyme aromatic L-amino acid decarboxylase. This enzyme is responsible for the decarboxylation of L-DOPA to dopamine, and 5-hydroxytryptophan (5-HTP) to serotonin. By inhibiting this enzyme, AADC inhibitors prevent the synthesis of these neurotransmitters from their precursors, leading to altered neurotransmitter levels.

Clinical Uses

AADC inhibitors are used in the treatment of several conditions, including:

• Parkinson's disease: In combination with L-DOPA, AADC inhibitors are used to increase the availability of L-DOPA in the brain, thereby enhancing its effectiveness in treating Parkinson's disease symptoms.
• Dopamine-responsive dystonia (DRD): A rare disorder characterized by muscle contractions and involuntary movements. AADC inhibitors can help increase dopamine levels in the brain, alleviating symptoms of DRD.

Side Effects

The use of AADC inhibitors can lead to various side effects, including:

• Nausea and vomiting
• Orthostatic hypotension
• Headaches
• Dizziness
• Insomnia

These side effects are often related to the altered levels of neurotransmitters caused by the inhibition of the AADC enzyme.

Examples of AADC Inhibitors

Some examples of aromatic L-amino acid decarboxylase inhibitors include:

• Carbidopa
• Benserazide

These drugs are often used in combination with L-DOPA in the treatment of Parkinson's disease and other conditions.

Future Directions

Research is ongoing into the development of new AADC inhibitors with improved efficacy and fewer side effects. Additionally, studies are exploring the use of these inhibitors in the treatment of other neurological and psychiatric disorders beyond those currently approved.